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AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
630 PM EDT FRI MAY 22 2015

.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.

&&

.SYNOPSIS...
ISSUED AT 139 AM EDT FRI MAY 22 2015

HIGH PRESSURE AND AN UPPER LEVEL RIDGE IS EXPECTED TO BRING DRY
WEATHER TO CENTRAL INDIANA THROUGH SUNDAY. AS THE HIGH DRIFTS TO
THE EAST...WARMER TEMPERATURES ARE EXPECTED EACH DAY AS THE
WEEKEND PROGRESSES.

BY SUNDAY NIGHT AND MONDAY...WARMER AND MORE HUMID AIR WILL
ARRIVE IN THE AREA AND AN UPPER LEVEL WEATHER DISTURBANCE WILL
ARRIVE IN THE OHIO VALLEY TO BRING CHANCES FOR SHOWERS AND
THUNDERSTORMS AS THE HOLIDAY WEEKEND CONCLUDES. 

A WARMER...MORE HUMID AT WETTER WEATHER PATTERN IS EXPECTED NEXT
WEEK...PROVIDING CHANCES FOR SHOWERS EACH DAY.

&&

.NEAR TERM /TONIGHT/...

ISSUED AT 139 AM EDT FRI MAY 22 2015

SURFACE ANALYSIS EARLY THIS AFTERNOON SHOWS A WEAK SURFACE TROUGH
STRETCHING ACROSS NRN OHIO TO CENTRAL INDIANA. NOT A CLOUD WAS
ASSOCIATED WITH THIS FEATURE. STRONG HIGH PRESSURE WAS IN PLACE IN
THE WAKE OF THIS FEATURE BUILDING SOUTHEAST. WATER VAPOR IMAGERY
SHOWS AN SHORT WAVE OVER THE CENTRAL PLAINS...WITH SHOWERS AND
TSRA OVER NEBRASKA...KANSAS AND OKLAHOMA. 

FORECAST SOUNDINGS AND TIME HEIGHTS CONTINUE TO SHOW A DRY COLUMN
ACROSS CENTRAL INDIANA TONIGHT WITH SUBSIDENCE. WATER VAPOR
SHOWING SOME HIGH CLOUDS OVER MISSOURI ARE EXPECTED TO ADVECT INTO
THE OHIO VALLEY LATE TONIGHT AND FORECAST SOUNDINGS DO REVEAL SOME
HIGH LEVEL SATURATION AT THAT TIME. THUS WILL TREND TOWARD A
MOSTLY CLEAR EVENING...WITH INCREASING CLOUDS OVERNIGHT. GIVEN THE
EXPECTED INCREASING CLOUDS ALOFT...WILL TREND LOWS AT OR ABOVE
MAVMOS.

&&

.SHORT TERM /SATURDAY THROUGH MEMORIAL DAY/...

ISSUED AT 139 AM EDT FRI MAY 22 2015

FORECAST CHALLENGE THROUGH THIS PERIOD WILL BE THE INTRODUCTION OF
POPS ON SUNDAY NIGHT AND INTO MONDAY.

DRY WEATHER IS EXPECTED TO CONTINUE THROUGH SUNDAY AS GFS AND NAM
SUGGEST THAT STRONG RIDGING ALOFT WILL BUILD ACROSS CENTRAL
INDIANA. THE PROTECTIVE RIDGE WILL STEER ANY WEAK SHORT WAVES WELL
NORTH OF CENTRAL INDIANA TIME HEIGHT SECTIONS THROUGH SATURDAY
NIGHT SHOW SUBSIDENCE AS SURFACE HIGH PRESSURE DRIFTS THROUGH THE
GREAT LAKES TOWARD THE MIDDLE ATLANTIC STATES. FORECAST SOUNDINGS
SHOW REACHABLE CONVECTIVE TEMPS IN THE UPPER 70S...BUT WITH A MID
LEVEL INVERSION IN PLACE ALONG WITH LIMITED CAPE...ONLY A FEW CU
WILL BE EXPECTED. WILL TREND HIGHS AT OR ABOVE MAVMOS AS PLENTY OF
SUN WILL BE EXPECTED ALONG WITH SOUTHERLY SURFACE FLOW IN PLACE.
WITH SIMILAR CONDITIONS EXPECTED ON SATURDAY NIGHT...ALONG WITH
BROAD WARM AIR ADVECTION...WILL TREND LOWS AT OR ABOVE MAVMOS.

ON SUNDAY...MUCH BETTER ISENTROPIC LIFT BEGINS WITH SPECIFIC
HUMIDITIES OVER 6 G/KG WILL BE IN PLACE AS SEEN ON THE GFS 300K
SURFACE. HOWEVER FORECAST SOUNDINGS FAIL TO SHOW DEEP SATURATION
ALONG WITH UNATTAINABLE CONVECTIVE TEMPS. FURTHERMORE...NO DYNAMIC
SUPPORT IS AVAILABLE ALOFT AND THE LOWER LEVEL FLOW REMAINS UNDER
THE INFLUENCE OF HIGH PRESSURE. THUS WILL TREND TOWARD A DRY
FORECAST FOR SUNDAY...HOWEVER...MORE CLOUD COVER WILL BE EXPECTED
AMID THE STRONG WARM AIR ADVECTION. WILL USE A BLEND FOR HIGH
TEMPERATURE.

BY LATE SUNDAY NIGHT AND INTO MONDAY...THE PROTECTIVE RIDGE
BUILDS EAST OF CENTRAL INDIANA. THE GFS THEN SHOWS A BROAD SHORT WAVE
OVER THE MIDDLE MISSISSIPPI RIVER VALLEY POISED TO PUSH INTO THE
OHIO VALLEY FOR MONDAY. FORECAST SOUNDINGS BEGIN TO SHOW DEEP
SATURATION ON MONDAY...FOLLOWED BY ATTAINABLE CONVECTIVE TEMPS
WITH LIMITED CAPE. 300K GFS ISENTROPIC SURFACE SHOW A VERY MOIST
AIR MASS IN PLACE WITH SPECIFIC HUMIDITIES OVER 7 G/KG. GOOD
SUPPORT APPEARS IN PLACE ALOFT ALSO. WILL TREND POPS AT OR ABOVE
MAVMOS AND MEXMOS FOR LATE SUNDAY NIGHT AND MONDAY. WILL TREND
TEMPS ABOVE MAVMOS FOR LOWS ON SUNDAY NIGHT AND COOLER THAN MAVMOS
ON MEMORIAL DAY. 

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...

ISSUED AT 242 PM EDT FRI MAY 22 2015

AN UPPER RIDGE OFF THE EAST COAST COMBINED WITH UPPER TROUGHING 
ACROSS THE WESTERN AND CENTRAL U.S. WILL KEEP CHANCES FOR SHOWERS 
AND THUNDERSTORMS IN THE FORECAST THROUGHOUT THE LONG TERM. 
SOUTHWESTERLY FLOW WILL ALLOW TEMPERATURES TO RUN ABOVE NORMAL 
THROUGH THE PERIOD WITH HIGHS IN THE UPPER 70S TO LOWER 80S AND LOWS 
IN THE 60S. MODELS ARE SHOWING SOME DIFFERENCES WITH TIMING ON 
SPECIFIC WAVES MOVING THROUGH THE FLOW SO BEST BET AT THIS POINT IS 
TO ACCEPT INITIALIZATION OF CHANCE POPS THROUGH MOST OF THE PERIOD.  

&&

.AVIATION /DISCUSSION FOR 230000Z TAF ISSUANCE/...

ISSUED AT 630 PM EDT FRI MAY 22 2015

EXCELLENT CONFIDENCE THAT VFR CONDITIONS WILL CONTINUE THROUGHOUT 
THE TAF PERIOD. REGARDING CLOUD COVER...SHOULD ONLY SEE SCATTERED 
DIURNAL CU 5K FEET AND ABOVE AND INCREASING CIRRUS AND AC. 

WINDS WILL BECOME LIGHT TO CALM NEAR OR JUST AFTER ISSUANCE TIME AND 
THEN VEER TO SOUTHEAST AND SOUTH LESS THAN 10 KNOTS AFTER 15Z 
SATURDAY.

&&

.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SYNOPSIS...PUMA
NEAR TERM...PUMA
SHORT TERM...PUMA
LONG TERM....CP
AVIATION...MK

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